$\mathrm{8,7}\cdot 10\cdot 10\cdot 10\cdot 10\cdot 10=8700008\{,\}7\backslash cdot\; 10\backslash cdot\; 10\backslash cdot\; 10\backslash cdot\; 10\backslash cdot\; 10=870000$ $\Rightarrow \backslash Rightarrow$

$\mathrm{8,7}\cdot {10}^5=8700008\{,\}7\backslash cdot\; 10^5=870000$